This invention relates to vanadium catalysts for olefin polymerization.
Vanadium compounds display catalytic activity in a number of diverse chemical reactions. Since vanadium is closely related to both chromium and titanium in the Periodic Table, it is only natural that it has been tried in place of chromium or titanium as a catalyst for the polymerization of mono-1-olefins. However, vanadium catalysts have not been as commercially successful as titanium or chromium catalysts for olefin polymerization. Supported vanadium catalysts have been particularly disappointing as olefin polymerization catalysts. To a substantial extent, the greatest success with vanadium in the prior art is an olefin polymerization catalyst which has been in systems more analogous to unsupported titanium systems, i.e. VOCl.sub.3, VCl.sub.4 or VCl.sub.3 used with a reducing agent such as an aluminum hydride. However, the natural tendency of vanadium to catalyze reactions other than polymerization has been a constant problem limiting its usefulness in olefin polymerization.
It would be desirable in some applications to be able to obtain a supported system having the kind of molecular weight sensitivity to hydrogen that is displayed by unsupported titanium catalyst systems.